This invention relates to improved catalytic compositions having utility in hydrocarbon conversion processes. In a specific aspect, the invention relates to improved catalytic compositions having utility in hydrogen treating of hydrocarbon feed materials.
Catalytic compositions containing a catalytically active metallic component deposed on a non-zeolitic, refractory inorganic oxide support are well known as are numerous uses therefor. Familiar examples include petroleum and synthetic crude oil hydrotreating and hydrocracking catalysts comprising a Group VIB and/or VIII metal such as cobalt, nickel molybdenum and/or tungsten deposed on a non-zeolitic, refractory inorganic oxide such as alumina, silica, magnesia, etc. and olefin polymerization catalysts comprising a Group VIB metal deposed on silica or silica-alumina supports.
It also is known that the activity or performance of catalysts of the type described hereinabove for reactions such as hydrocracking, disproportionation and oligomerization can be improved or modified by inclusion in the catalyst of a crystalline molecular sieve zeolite component. Thus U.S. Pat. No. 3,649,523 (Bertolacini et al.) discloses a hydrocarbon conversion process, and particularly hydrocracking and disproportionation of petroleum hydrocarbon feed materials, carried out in the presence of improved catalysts comprising a metallic component having hydrogenating activity deposed on a support component comprising a large pore crystalline aluminosilicate and a porous support material such as alumina, silica or aluminum phosphate. U.S. Pat. No. 3,894,930 and U.S. Pat. No. 4,054,539 (both Hensley) disclose hydrocracking in the presence of improved catalysts comprising a metallic hydrogenating component and a support component comprising ultrastable large pore crystalline aluminosilicate and silica-alumina. U.S. Pat. No. 3,876,522 (Campbell et al.) discloses preparation of lube oils by a process that includes a hydrocracking step in which there are employed catalysts containing a composite of a crystalline aluminosilicate zeolite component and a porous refractory oxide component such as alumina or silica, such composite containing deposited or exchanged catalytic metals. U.S. Pat. No. 4,029,601 (Wiese) discloses oligomerization of alkenes using a cobalt oxide-active carbon composite supported on a refractory oxide such as silica or alumina and/or crystalline aluminosilicate zeolites. Other processes in which catalysts comprising catalytically active metals and a support component comprising a porous oxide and a crystalline molecular sieve zeolite are useful include isomerization of alkylaromatics and alkylation of aromatics and paraffins.
It also is known that the performance of various catalysts containing catalytically active metals deposed on a non-zeolitic, refractory inorganic oxide support component can be improved or modified by inclusion of phosphorus in the catalytically active metallic component or through the use of phosphorus compounds in catalyst preparation. For example, U.S. Pat. No. 3,287,280 (Colgan et al.) discloses that the use of phosphoric acid solutions of nickel and/or molybdenum salts to impregnate non-zeolitic supports such as alumina or silica leads to improved dispersion of catalytically active metals on the support surface and improved results in hydrodesulfurization of petroleum hydrocarbon feeds. The patentee also discloses that phosphoric acid residues remaining in the catalyst impart thermal stability thereto. U.S. Pat. No. 3,840,472 (Colgan) contains a similar disclosure with respect to the use of phosphoric acid impregnating solutions of active metal salts. U.S. Pat. No. 4,165,274 (Kwant) discloses a two-step process for hydrotreating and hydrocracking tar sands oils wherein hydrotreating takes place in a first stage in the presence of an alumina-supported, fluorine and phosphorus-containing nickel-molybdenum catalyst, after which hydrocracking is conducted in the presence of a catalyst-containing nickel and tungsten supported on a low-sodium, Y-type molecular sieve support component. U.S. Pat. No. 3,985,676 (Rekers et al.) discloses catalysts for polymerization of olefins prepared by deposition of various organophosphorus compounds of chromium onto high surface area non-zeolitic supports such as silica or silica-alumina followed by thermal activation of the result.
Notwithstanding similarities in the basic catalytic composition--catalytically active metal component deposed on non-zeolitic refractory inorganic oxide support component--into which phosphorus or crystalline molecular sieve zeolite components have been incorporated according to the above-described proposals, the reported effects of the zeolite and phosphorus components are, in many respects, sufficiently unrelated as to mitigate against attempting to combine the effects of the components into a single catalyst. For example, the improved hydrocracking activity of the above-described zeolite-containing catalysts typically would not be desired in a hydrodesulfurization or hydrodenitrogenation catalyst because in typical hydrotreating processes employing such catalysts, it is preferred to limit cracking. Similarly, the improved hydrodesulfurization activity of phosphorus-promoted catalysts such as those of Colgan et al. would be of little consequence within the context of a cracking, alkylation, isomerization or disproportionation process. On the other hand, we have previously found that a phosphorus component incorporated into the hydrogenating component of certain hydrotreating catalysts exerts a promotional effect with respect to denitrogenation of high nitrogen feeds while crystalline molecular sieve zeolite components incorporated into catalysts containing similar active metals but free of phosphorus exerts a promotional effect with respect to denitrogenation and hydrocracking reactions.
It also is known from Rabo, Zeolite Chemistry And Catalysis, ACS Monograph 171, American Chemical Society, pages 294-297 (1976), that many crystalline molecular sieve zeolites possess only limited stability with respect to strong acids such as the phosphoric acid used according to Colgan et al. Accordingly, it can be speculated that attempts to combine the promotional effects of phosphoric acid and crystalline molecular sieve zeolites have been limited by concern over destruction of the zeolite component.
U.S. Pat. No. 3,617,528 (Hilfman), which is directed to preparation of supported nickel-containing catalysts by coextrusion of a phosphoric acid solution of nickel or nickel and Group VIB metal compounds and an alumina-containing carrier, suggests the use of carriers containing silica and alumina that are amorphous or zeolitic in nature. Column 2 lines 39-43. Crystalline aluminosilicate zeolites specifically disclosed by Hilfman are mordenite, faujasite and Types A and U molecular sieves. Column 3 lines 42-46. Hilfman does not address the effect of the acid on zeolite integrity or crystallinity, nor is there any disclosure or suggestion as to whether any zeolite employed in the disclosed preparations would remain intact in the final catalyst. In fact, none of the disclosed crystalline aluminosilicate zeolites, or any other for that matter, is employed in the patentee's examples. Further, U.S. Pat. No. 3,706,693 (Mickelson et al. '693) and U.S. Pat. No. 3,725,243 (Hass et al.) teach that exposure of zeolites to strong acids such as phosphoric acid destroys zeolite crystallinity and integrity. In fact, both Mickelson et al. '693 and Hass et al. are directed specifically to catalyst preparations in which impregnation of crystalline aluminosilicate-containing supports with phosphoric acid solutions of salts of hydrogenating metals results in destruction of zeolite crystallinity. Further, three of the four crystalline aluminosilicate zeolites specifically disclosed by Hilfman (faujasite, mordenite and Type A molecular sieve) are included among the crystalline aluminosilicate zeolites that are preferred for use in Mickelson et al.'s and Hass et al.'s zeolite-destructive preparations. The aforesaid Rabo publication teaches that among Zeolite A, faujasite and mordenite, only the latter exhibits appreciable acid stability.
U.S. Pat. No. 3,905,914 (Jurewicz et al.) is directed to preparation of oxidation catalysts by mixing a vanadium compound, zirconium salt and hydrogen halide, and then adding phosphoric acid or a compound hydrolyzable to phosphoric acid. The result is refluxed to form a gel which then is dried, or "used to impregnate a suitable carrier, such as alumina, alundum, silica, silicon carbide, silica-alumina, zirconia, zirconium phosphate and/or a zeolite." Column 2 lines 47-51. Jurewicz et al. does not identify any zeolites nor do the patentee's examples illustrate preparation of a supported catalyst. Also, no consideration is given to acid stability of zeolites and there is no indication whether any zeolite used in the disclosed catalyst preparation would remain intact.
Similar to the Mickelson et al. '693 and Hass et al. patents discussed hereinabove, U.S. Pat. Nos. 3,749,663, 3,749,664 and 3,755,150 (all Mickelson) are directed to impregnation of support materials with phosphoric acid solutions of salts of catalytically active metals. Although none of these patents discloses impregnation of support materials containing a zeolite component, each patent expressly cautions against exposure of supports containing aluminum ions to phosphoric acid at relatively low pH stating that reaction of the acid and aluminum degrades the support, fouls the impregnating solution and results in formation of undesirable chemical forms in the finished catalyst. (See Mickelson '663 at Column 8 lines 60-69, Mickelson '664 at Column 8 lines 6-15, Mickelson '150 at Column 9 lines 12-21.)
U.S. Pat. No. 3,836,561 (Young) also deals with acid treatment of crystalline aluminosilicate zeolites. According to Young, alumina-containing compositions, including those containing crystalline aluminosilicate zeolites, are reacted with aqueous acids including hydrochloric, sulfuric, nitric, phosphoric and various organic acids, at a pH below about 5 in the presence of an ionizable salt that is soluble in the aqueous phase, and then the result is washed, dried and calcined. The result of such treatment is removal of aluminum from the alumina-containing composition, replacement thereof with metallic cations if the ionizable salt is one containing cations that can be exchanged into the zeolite, increased porosity and decreased bulk volume of the catalyst. The resulting compositions are said to have utility as absorbents, ion exchange resins, catalysts and catalyst supports. Acid-stable zeolites and the effects of acid treatment on zeolite crystallinity are discussed at Column 2 lines 61-68. Of course, Young's acid treatment differs from the use of phosphoric acid according to the patents discussed hereinabove in that Young's purpose is to remove aluminum from the composition rather than to incorporate phosphorus into it. It also differs from the patents discussed hereinabove in that the disclosed compositions lack a catalytically-active metallic component deposed on the alumina-containing carrier.
Other patents and publications that may be of interest to the present invention in disclosing treatment of crystalline molecular sieve zeolites or compositions containing the same with phosphoric acid and other phosphorus compounds to incorporate phosphorus into the zeolite are U.S. Pat. No. 3,962,364 (Young) and U.S. Pat. Nos. 4,274,982, 4,276,437 and 4,276,438 (all Chu). According to these patents, suitable phosphorus compounds include halides, oxyhalides, oxyacids and organophosphorus compounds such as phosphines, phosphites and phosphates. Incorporation of phosphorus according to these patents is reported to improve para-selectivity in alkylation reactions. Chu '982 further discloses treatment of the phosphorus-containing zeolites with magnesium compounds. Chu '437 discloses impregnation of the phosphorus treated compositions with solutions of gallium, iridium or thallium compounds. Chu 438 contains a similar disclosure with respect to impregnation of compounds of silver, gold and copper. Both patents disclose use of acid solutions of the metals as impregnating solutions, with hydrochloric, sulfuric and nitric as well as various organic acids being disclosed. None of these patents discloses or suggests the use of phosphoric acid impregnating solutions nor is there any suggestion of a catalyst containing an active metallic component which contains phosphorus. Rather, the respective patentees' phosphorus is incorporated into the zeolite.
British No. 1,555,928 (Kouwenhaven et al.) discloses crystalline silicates of specified formula having utility in a wide range of hydrocarbon conversions. Impregnation of the silicates with catalytic metals is disclosed as is promotion or modification with halogens, magnesium, phosphorus, boron, arsenic or antimony, (Page 6 lines 33-54); with incorporation of phosphorus into the silicate to improve alkylation selectivity, as in the above-described Chu patents, being specifically disclosed.
It also is known that phosphine or other organophosphorus complexes of various metal salts can be employed in preparation of various supported catalyst compositions. For example, U.S. Pat. No. 3,703,561 (Kubicek et al.) discloses catalysts for olefin disproportionation comprising a reaction product of (1) an organoaluminum halide, aluminum halide or combination thereof with each other or with another organometallic halide and (2) a mixture of a salt of copper, silver or gold with a complexing agent which may be an organophosphine. Reaction of components (1) and (2) is conducted in the presence of a solvent for the reactants, in the substantial absence of air and at temperatures low enough to avoid decomposition of the reactants. It also is disclosed to provide the catalysts in supported form by impregnating a support such as a non-zeolitic, refractory inorganic oxide or a zeolite with the reaction product, or by impregnation with one of the reactants followed by addition of the other. Kubicek et al. also states that if such supported catalysts are to be activated by calcination the calcination should take place prior to impregnation with the active species, i.e., the reaction product of components (1) and (2). It is unclear whether residues of any organophosphine compound used in preparation of the catalysts of Kubicek et al. would remain in association with the active metallic species. In any event, the catalyst preparation according to this patent is conducted under conditions designed to avoid conversion of any such organophosphine residues to an oxygenated phosphorus component such as that required according to the present invention.
U.S. Pat. No. 3,721,718 (Hughes et al.) and U.S. Pat. No. 4,010,217 (Zuech) contain disclosures similar to that of Kubicek et al. with respect to use of organophosphorus complexes of various metal salts in preparation of olefin disproportionation catalysts. Like Kubicek et al., both Hughes et al. and Zuech contemplate supported catalysts; however, both patentees also state that if activation by calcination is desired, it should be accomplished by calcination of support prior to incorporation of active metals.
Another patent disclosing the use of metal complexes in catalyst preparation is U.S. Pat. No. 3,849,457 (Haag et al.) which is directed to preparation of carboxylic acids by hydrogenolysis of esters. The catalysts of Haag et al. comprise a hydrogenating metal component and a solid acid component such as a zeolite which components may be employed as a loose physical admixture or by combining the two components into a single particle. Various methods for combining the two components into a single particle are disclosed at Column 6 line 64-Column 7 line 44. One of these involves mixing a solution of a metal pi-complex with the acid solid and then decomposing the complex to form elemental metal and depositing the elemental metal onto the acid solid. A specific metal complex employed in this preparative scheme is tetra(triphenylphosphine)palladium(II) dibromide. Another preparative method useful with respect to zeolitic acid solid components involves incorporation of the hydrogenation component by conventional methods such as ion exchange or impregnation. None of the disclosed methods would result in association of an oxygenated phosphorus component with the metallic component of the patentees' catalyst.
U.S. Pat. No. 4,070,403 (Homeier) discloses a hydroformylation catalyst comprising a cobalt compound and a zeolite-alumina hydrosol dispersion. The cobalt compound is chemically bonded to the alumina-zeolite dispersion by a vapor-phase impregnation technique. Suitable cobalt components of the disclosed catalysts include various salts such as halides, nitrate and various carboxylates as well as organophosphine complexes. Homeier does not disclose or suggest the presence of an oxygenated phosphorus component in the final catalyst, nor does the patentee attribute any promotional effect to phosphorus.
It can be appreciated from the foregoing that efforts to include both a crystalline molecular sieve zeolite component and a phosphorus component in catalysts comprising an active metal component deposed on a non-zeolitic refractory inorganic oxide component in such a manner that the promotional effects of both the phosphorus and the zeolite are retained have been largely unsuccessful. In those instances in which an attempt has been made to incorporate a promoting phosphorus component through the use of phosphoric acid impregnating solutions of compounds of active metals, such use of phosphoric acid in conjunction with a crystalline aluminosilicate zeolite-containing composition often results in destruction of the crystalline aluminosilicate zeolite component. Other proposals such as those involving use of organophosphorus complexes of various metal salts to aid impregnation or deposition of active metals into or onto support result in only incidental, if any, incorporation of phosphorus into the final catalyst, and phosphorus so incorporated appears lacking in promotional effect.
It would be desirable to provide an improved catalytic composition in which both phosphorus and crystalline molecular sieve zeolite components are present in a form capable of exerting a promotional effect. It is an object of this invention to provide an improved catalytic composition. A further object of the invention is to provide for the use of such catalytic compositions in hydrocarbon conversion processes. A still further object is to provide for the preparation of catalysts in which improved performance is attained through incorporation of crystalline molecular sieve zeolite and phosphorus components. Other objects of the invention will be apparent to persons skilled in the art from the following description and the appended claims.
We have now found that the objects of this invention can be attained by incorporation of an oxygenated phosphorus component into the catalytically active metallic component of a catalytic composition and incorporation of selected crystalline molecular sieve zeolite components into the support component of the composition. Advantageously, the crystalline molecular sieve zeolite components of the invented catalysts are derived from acid-tolerant crystalline molecular sieve zeolites, and accordingly, phosphorus component can be incorporated without substantial destruction of zeolite integrity or crystallinity. Further, the phosphorus component is incorporated into the metallic component in a form capable of exerting a promotional effect. Thus, as demonstrated in the examples appearing hereinbelow, the catalysts of the invention, wherein an oxygenated phosphorus component is incorporated into a catalytically active metallic component which is deposed on or associated with a support component comprising at least one crystalline molecular sieve zeolite component and a non-zeolitic, refractory inorganic oxide matrix component, are superior to catalyst compositions that are identical but for the inclusion of a phosphorus component, or but for inclusion of the zeolite component, in a variety of catalytic processes. Accordingly, the overall effect of the phosphorus and zeolite components on performance of the basic catalytically active composition comprising a metallic component and a non-zeolitic, refractory inorganic oxide component is greater than the effect of either component alone in a variety of reactions.
In addition to the patents and publications discussed hereinabove, U.S. Pat. No. 4,228,036 (Swift et al.), and U.S. Pat. No. 4,277,373 (Sawyer et al.) may be of interest to the present invention in disclosing catalytic compositions containing phosphorus and zeolite components. Specifically, Swift et al. discloses an improved catalytic cracking catalyst comprising an alumina-aluminum phosphate-silica matrix composited with a zeolite component having cracking activity, such as a rare earth-exchanged Y-type crystalline aluminosilicate zeolite. Swift et al. does not disclose inclusion of an active metallic component into such catalysts. Further, in contrast to the catalysts of the present invention, wherein an oxygenated phosphorus component is included in an active metallic component, the phosphorus component of Swift et al.'s catalysts is included in a refractory oxide material.
Sawyer et al. discloses hydroprocessing catalysts comprising a Group VIB and/or VIII metal component composited with an ultrastable Y-type crystalline aluminosilicate zeolite and an alumina-aluminum fluorophosphate component. The catalyst also may contain an alumina gel-containing matrix. Although an essential component of Sawyer et al.'s catalyst is the aluminum fluorophosphate component of the support, it also is to be noted that patentee discloses use of phosphomolybdic acid to impregnate a support containing a Y-type crystalline aluminosilicate and alumina-aluminum fluorophosphate in Example 1 (see Column 5 lines 21-25). According to the example, however, it appears that there was no incorporation of a phosphorus component into the active metal component of the catalyst because the table at Column 5 lines 42-52 fails to report phosphorus content other than that contained in the aluminum fluorophosphate component of the support. Table 2 of Sawyer et al. also reports on a comparative catalyst C containing specified levels of alumina, Y-type zeolite, nickel oxide, molybdenum oxide, and phosphorus pentoxide. For catalyst C to have been a fair comparator for the catalysts of Sawyer et al.'s invention, the phosphorus pentoxide component must have been present in a manner similar to the fluorophosphate component of the patentees' catalysts, i.e., as part of the support. As such, Sawyer et al. fails to disclose or suggest a catalyst containing phosphorus as an essential part of the active metal component.